This invention relates to the keying of a shielded electrical connector assembly for mating with a mating electrical connector and also relates to a key for use in such an assembly, and to back shells therefor.
U.S. Patent Ser. No. 3,555,491 discloses an electrical connector provided with coding keys for mating with those of a mating electrical connector. Each key comprises a keying part projecting forwardly of the connector and behind the keying part and spaced rearwardly thereof a part of regular polygonal cross section received in a cavity of the same cross section in an insulating housing of the connector. The polygonal part of the key can therefore be inserted into the cavity in a number of different angular orientations depending upon the number of flats that the polygonal part has. The keying part of the key is such that it can only be mated with a complementary key having the same angular orientation. This ensures that the connector can only be mated with a mating connector the keys of which have said same angular orientation. Each key has a through axial passage for receiving a jack screw for securing the connector to the mating connector. U.S. Patent Ser. No. 2,902,665, similarly discloses an electrical connector having keys for receiving jack screws, each key having a polygonal part for reception in a polygonal cross section opening. In this case, the opening is formed in a flange projecting from a protective shell of the connector. Each key is secured in its opening by means of a collar on one side of the flange and a nut threaded onto the key on the other side of the flange. In order to change the axial orientation of the key, the nut must be loosened and then re-tightened. There is disclosed in U.S. Patent Ser. No. 3,177,461, a printed circuit edge connector having keys for mating with complementary keys on a printed circuit board, each key of the edge connector comprising a part in the form of a regular polygon and a keying part of substantially semi-circular cross section, formed integrally therewith. The polygonal part has a central hole receiving a screw threaded pin which in turn receives a nut which can be tightened to secure the key in a selected angular orientation with respect to a reduced cross section end portion of the housing of the connector, through which portion the pin extends. The polygonal part is retained in its selected angular orientation, before the nut is tightened, by the engagement of an end face of the connector housing with a flat of the polygonal part. U.S. Patent Ser. No. 4,929,184 relates to a shielded electrical connector, the shield of which has end flanges with polygonal openings therein for receiving polygonal parts of keys. Each key has a threaded shank receiving a nut for securing the key in its opening, or has a tapped bore receiving a jack screw which serves to secure the key in its opening. There is disclosed in U.S. Patent Ser. No. 4,934,950, a key having a polygonal part which is secured in a polygonal cross section opening in a flange of an electrical connector housing by means of a jack screw having smooth shank which is inserted through the key and into a smooth bore of a smooth bored nut. A pin in inserted through a radial hole in the nut and through an aligned hole in the shank of the jack screw. U.S. Patent Ser. No. 4,934,950 further discloses a key for mating with the key just described, having a polygonal cross section part which is received in a polygonal opening in the flange of the mating connector housing, a screw threaded shank projecting from the polygonal part, and receiving a locking ring for securing the key in its opening.